The prior art design of electro-optical connector modules included in active device which had a hermetically sealed window in a cap and some type of lens mounted with the cap so that the optical signal had to transfer between or pass through four optical interfaces. It may be noted that LED's transmit (Tx) into multimode fiber, for short distances, as lower speed signal rates do not require differing lensing schemes from the PIN (P doped Insulator, N doped) photo detector. (Rx) Further, because different optical properties and/or configurations are desirable for receiving and transmitting, the prior art devices were manufactured using different techniques, optimal elements, and spacings dependent upon whether the device was to transmit optical energy or to receive optical energy. It was further found in the prior art devices that movement of the fiber optic cable would affect the signal conversion efficiency due to misalignment of the optical signals relative the active device. Further, since prior art modules were typically assembled using epoxy or solder, a diode which may have been optimally aligned with the window, the lens, and the fiber would not remain so due to the creep that tends to occur with epoxy and solder underload over a period of time. Finally, the prior art devices have been typically designed such that an adjesive, an encapsulant, a threaded type or clamp-type connector is used to encase the active device into the connector module. LED's in multimode, short distance, low speed situations have sometimes used a "snap-in" lock-type mechanism.
The present device overcomes many of these limitations by incorporating a combination hermetic seal window as a single lens of the gradient index lens type. This same lens can be utilized in both the transmit and receive mode by changing the length of the lens within a barrel-shaped portion of the active device. As designed, the header-cap assembly can be, and is laser welded together at the time of alignment thus, assuring that there will be no misalignment creep with aging. The header-cap assembly is designed as part of a tongue-and-groove combination with skirts on the connector module so that the active device can merely be slipped into place to engage both the tongue-and-groove locking device as well as an alignment clip which coacts with a projecting fiber optic cable used to maintain alignment between the active device and the cable, to help provide precise positioning in the longitudinal axis of the two devices and to maintain conversion efficiencies even though the cable is moved due to the floating of the active device as a sub-assembly within the skirts of the module.
It is therefore an object of the present invention to provide an improved optoelectrical connection module.